1. Field of the Invention
The present invention relates to a grinding method of grinding the back side of a wafer or chip having a bump on the front side thereof.
2. Description of the Related Art
In a semiconductor device fabrication process, a plurality of crossing division lines called streets are formed on the front side of a silicon wafer or compound semiconductor wafer to thereby partition a plurality of regions where devices such as ICs and LSIs are respectively formed. The back side of the wafer is ground to reduce the thickness of the wafer to a predetermined thickness. Thereafter, the wafer is divided along the division lines to obtain individual semiconductor devices.
A grinding apparatus called a grinder is widely used to grind the back side of a wafer. The grinder includes a chuck table for holding a workpiece and grinding means opposed to the chuck table. In grinding the workpiece, a protective tape as disclosed in Japanese Patent Laid-open No. Hei 11-307620, for example, is attached to the front side of the workpiece, so as to protect the devices formed on the front side of the workpiece. The workpiece is held under suction through the protective tape on the chuck table of the grinder in the condition where the back side of the workpiece is exposed, and the back side of the workpiece is ground by abrasive members included in the grinding means.
As a technique for realizing a reduction in size and weight of a semiconductor device, a mounting method called flip-chip bonding has been put into actual use in recent years. In such flip-chip bonding, a plurality of metal projections called bumps each having a height of about 10 to 100 μm are formed on the front side of the device, and these bumps of the device are opposed to electrodes formed on a wiring board and bonded directly to the electrodes.